Chest
Volume 140, Issue 5, November 2011, Pages 1177-1183
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Original Research
Obstructive Lung Diseases
Validation of a Novel Risk Score for Severity of Illness in Acute Exacerbations of COPD

https://doi.org/10.1378/chest.10-3035Get rights and content

Background

Clinicians lack a validated tool for risk stratification in acute exacerbations of COPD (AECOPD). We sought to validate the BAP-65 (elevated BUN, altered mental status, pulse > 109 beats/min, age > 65 years) score for this purpose.

Methods

We analyzed 34,699 admissions to 177 US hospitals (2007) with either a principal diagnosis of AECOPD or acute respiratory failure with a secondary diagnosis of AECOPD. Hospital mortality and need for mechanical ventilation (MV) served as co-primary end points. Length of stay (LOS) and costs represented secondary end points. We assessed the accuracy of BAP-65 via the area under the receiver operating characteristic curve (AUROC).

Results

Nearly 4% of subjects died while hospitalized and approximately 9% required MV. Mortality increased with increasing BAP-65 class, ranging from < 1% in subjects in class I (score of 0) to > 25% in those meeting all BAP-65 criteria (Cochran-Armitage trend test z = −38.48, P < .001). The need for MV also increased with escalating score (2% in the lowest risk cohort vs 55% in the highest risk group, Cochran-Armitage trend test z = −58.89, P < .001). The AUROC for BAP-65 for hospital mortality and/or need for MV measured 0.79 (95% CI, 0.78-0.80). The median LOS was 4 days, and mean hospital costs equaled $5,357. These also varied linearly with increasing BAP-65 score.

Conclusions

The BAP-65 system captures severity of illness and represents a simple tool to categorize patients with AECOPD as to their risk for adverse outcomes. BAP-65 also correlates with measures of resource use. BAP-65 may represent a useful adjunct in the initial assessment of AECOPDs.

Section snippets

Data Source

We used one of the clinical research databases from CareFusion (Clinical Research Services, CareFusion; Marlborough, Massachusetts) for the period from January 1, 2007, through December 31, 2007. This database records input from 177 hospitals on all acutecare admissions. Specifically, the database contains information concerning patient demographics, discharge diagnoses, length of stay, hospital charges, and hospital mortality. It also includes patient vital signs and results from laboratory

Results

The final cohort included 34,669 subjects, of whom 80.6% had a principal diagnosis of AECOPD and the remainder had acute respiratory failure noted as the principal diagnosis along with COPD as a secondary diagnosis. As shown in Table 1, the median age was 72 years and 46.4% were men. The most common comorbidities were hypertension, congestive heart failure, and diabetes mellitus.

Approximately 4% of patients died while in the hospital, and MV was required at any point in 9.2%. We observed the

Discussion

This analysis of a large cohort of patients with AECOPDs demonstrates that the BAP-65 class correlates well with multiple clinical outcomes ranging from in-hospital mortality and need for MV to LOS and cost. Furthermore, the BAP-65 system identifies subjects unlikely to ever need MV. Given that clinical decision making along with determinations as to the triage of patients is a complex process that requires an analysis of multiple factors beyond just severity of illness, the ability of BAP-65

Acknowledgments

Author contributions: Dr Tabak had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Shorr: contributed to study concept and design, analysis and interpretation of data, drafting and critical revision of the manuscript for important intellectual content, statistical expertise, and study supervision.

Dr Sun: contributed to study concept and design; acquisition, analysis, and interpretation of data; critical

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Funding/Support: The authors have reported to CHEST that no funding was received for this study.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).

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